[KS][KEY] Return on Button styles with controls disabled navigates to All screens #371

Part of #15. Found while doing #350.

Problem

On Native controls > Button styles, check "Disable controls" with a driver click on its box (tapOn: { point: "4%,50%", within: { id: native-controls-buttons-disabled } }), wait until the page is disabled, then pressKey: Enter. The Kitchen Sink leaves the screen and shows All screens (the catalog). Reproduced in English, light, on the driver backend, with and without the React Native Pressables #350 adds to the screen.

The default button is disabled at that point, so Return is not its key equivalent. Something else handles it and navigates: possibly a focused shell control such as the breadcrumb's "All screens" link. Which view has focus, and why, isn't known yet.

Acceptance

• Find which view handles Return there and why it has focus.
• Return on a screen whose default button is disabled does not navigate, or the behavior is documented as intended.
• A flow covers it.